Huge Icebergs Occur Infrequently, But Regularly

April 18, 2000

A huge iceberg that broke off from the Ross Ice Shelf in Antarctica a few weeks ago is not the largest iceberg ever recorded, contrary to some media reports. Some reports suggested the iceberg, first noticed in satellite photographs on March 17, 2000, by meteorologists at McMurdo Station, is just the kind of thing that one would expect if global warming is melting the polar icecaps -- except that the berg is neither unusual nor tied to global warming by experts.

According to the New York Times, the iceberg -- which is designated B-15 -- is the largest in more than four decades, and measures about 185 miles long by 23 miles wide, or slightly smaller than Connecticut.

However, a 1956 iceberg was reported by the crew of a U.S. Navy icebreaker to be about 208 miles long by 60 miles wide.

Such large chunks of the ice sheet -- which moves toward the sea at a rate of about half a mile per year -- are expected to break off every 50 to 100 years, according to Matthew Lazzara, a meteorologist with the Antarctic Meteorological Research Center at the University of Wisconsin in Madison.

Thus the new iceberg is nothing unusual.

A second iceberg, about one-third the size of the first, was apparently created when the first iceberg collided with the ice sheet. The smaller iceberg later broke into four pieces.